The present invention relates to a method of manufacturing cookware having a decorative design.
Copper and copper clad cookware are well know. However, the copper cladding hides the beauty of copper. Some styles of copper cookware have a base that is a laminate of copper with other metal, such as aluminum and stainless steel for protection.
Exposing at least a portion of the copper core normally hidden behind cladding is desirable as a decorative effect, but also helps the cook differentiate the cookware from similar cookware that does not have a highly conductive base or sidewalls.
One such novel design, now the subject of a commonly owned U.S. design patent application no. 29/313,712 filed Feb. 3, 2009, now U.S. Design Pat. No. D652,670, is shown in FIG. 1. As disclosed further herein and not admitted as prior art, such an ornamental appearance of cookware vessel 100 can be provided by an anodized aluminum portion that forms a vessel 110 for containing fluid, which is dark grey in color and a generally matte finish. The base 105 or bottom of vessel 100 is a laminate of copper cap which is attached to the aluminum vessel body 110 followed by a protective cap of stainless steel 130 attached to the copper base or cap 130. The stainless steel cap 130 does not extend upward to the anodized aluminum, but exposes an annular rim 114 of copper metal. This construction thus produces a decorative design of a grey body, with a bright copper rim between the bright silvery stainless steel base. FIG. 2A shows the construction of the vessel 100 in cross-section, with FIG. 2B showing a magnified partial view of the cookware wall adjacent the rim thereof.
This construction is preferred for protecting the copper layer with the stainless steel cap, and the scratch resistance of the anodized alumina body, as well as the higher thermal conductivity of the copper. However, similar appearing cookware can be made using paints or finishes to provide the matte color of the alumina; or plating can be used to create the visual impression of a thick copper layer in the cap.
It is therefore a first object of the present invention to provide an improved method for fabricating a cookware article having a portion of exposed copper adjacent an anodized aluminum layer.
It is also an object of the invention to provide improved method for fabricating a cookware article having a portion of exposed copper adjacent an anodized aluminum layer wherein a steel cap protects the lower portion of the exposed copper so that only a band or ring remains visible.
It is a further object of the invention to provide such methods wherein the seams or margins between the different layers, and in particular between the copper and aluminum has a regular sharp transition along the entire periphery of the vessel, and to do so in a cost effective manufacturing process.